Presentation on theme: "Younger Dryas Impact Study"— Presentation transcript:
1Younger Dryas Impact Study Undergraduate Research Experience 2008Elizabeth City State UniversityDr. Malcolm LeCompteMyAsia ReidLeroy LucasDevina Hughes
2Abstract "Younger Dryas Impact Study”- Summer 2008 The events precipitating the dramatic, millennial long climatic cooling known as the Younger Dryas, that occurred approximately 13,000 years ago remain a mystery. Recent evidence suggests an extraterrestrial impact on the Laurentide ice sheet may have provided the trigger for a massive influx of fresh glacial melt water theorized to have flooded the North Atlantic and shut down the Thermohaline circulation that moderates climate in the northern hemisphere.The apparent absence of an easily identified impact crater has focused the search for evidence of an impact on a search for extraterrestrial markers embedded in the Earth’s sedimentary record.Association of an impact with coincident reduction in the numbers of megafauna species and human population of North America has suggested a strategy for the search for evidence of the impact. If an impact is responsible for initiating the onset of the Younger Dryas, the ultimate disappearance of megafauna species and the decline in human population, then the evidence should lie at the sedimentary boundary (YDB) separating the Younger Dryas from the preceding Bolling-Allerod at a depth corresponding to 12,900 years before present.Some of these evidential markers (magnetic grains and spherules, charcoal, and glass-like carbon) was relatively easy to extract and identify while others (nanodiamonds and fullerenes) required great care, expensive instrumentation and considerable training. Fortunately, the vessels (carbon spherules) containing the more challenging markers were identified and extracted during the soil processing for magnetic spherules and charcoal. The research project also included an investigation of local paleo-lake depressions known to harbor impact markers and whose stratigraphy could have revealed a clearer understanding of the processes that shaped the coastal topography during the Younger Dryas. The research was carried out using a combination of Ground Penetrating RADAR (GPR) and sample coring to probe the subsurface deposits of selected depressions.
3What Happened 12, 900 Years Ago? That resulted in the near extinction of many species of MegafaunaThat led to the apparent disappearance of the Clovis Paleo-Indian culture?That filled Greenland ice cores with evidence of massive forest fires across the globe?That led to glacial melt water flooding the North Atlantic, disrupting salinity and interfering with ocean circulation patterns that warm Northern latitudes,And returned the Earth’s climate to its previous Ice Age conditions?
4What Do You Believe?Many theories exist to explain the Megafauna species disappearance:Some believed the “Clovis People” killed the animals for food. (KILL)…but who killed CLOVIS?Climate Change caused the animal’s food to disappear. (CHILL)…but COLD never killed them before!A plague wiped them out. (ILL)…All the species killed by the same FLU?The most recent proposal:A Comet (or comet fragments) hit North America 12,900 years ago.
5If So…This might have been the impact of the small comet or asteroid, which exploded in the upper atmosphere, or hit the Laurentide Ice sheet forming an ice walled crater, which subsequently melted leaving no primary evidence.Causing massive forest fires across North AmericaSoon enough, the atmosphere was filled with soot, and dust, blocking outSolar radiation for a long period of time, which resulted in a “nuclear winter”.Then snowfell, and glaciers reformed, and freezing temperatures persisted for centuries.
6Clovis Sites Clovis sites provide a reference date. No evidence of Clovis culture lies above the 12,900 year YDB.There are 50 known Clovis sites in North America that contain dark organic deposits, also known as “black mats” which mark the end of the Clovis Era.Black Layer
7Searching for Evidence of an IMPACT! Soil Sample Analysis ApproachMiles Point, Chesapeake Bay, MDIdentify a site with dated, vertical, stratigraphic exposure (e.g. River Bank, Cliff Face, Road Cut).Clovis artifacts provide a reference date, the Younger Dryas Boundary (YDB).Carbon 14 datingCollect soil samples above, at, and below the dated reference soil layer (YDB).Miles Point, Chesapeake Bay, MDEure Farm, Cross Neck Rd., Hertford, NCProcess soil samples to collect Impact MarkersConvert soil to slurry with waterPlastic bag covered super magnet used to extract magnetic particlesOrganic material floats and is skimmed from slurry surface.Eure Farm, Cross Neck Rd., Hertford, NC
8Impact MarkersGoalOur goal was to detect impact markers in any of the 4 samples collected from Miles Point:Magnetic Grains (found)Magnetic Spherules (not found)Carbon Spherules (found)Glass-like Carbon (found)Charcoal (found)Nano-Diamonds (found)
9Miles Point, Chesapeake Bay, MD Soil samples collected by Dr. Malcolm LeCompte on May 14th, 2008 processed and analyzed.One of the known Clovis SitesResults of Magnetic extractionEure Farm, Hertford, NC:Soil samples collected July 18th, 2008 but unprocessed.*trace- barely measurable.SampleTMass (g)Depth in. (cm)Total mass of Magnetic grains (g)Magnetic grain Fraction1263.522.5 (57.15)<0.01Trace*2185.524.5 (62.23)325826.5 (67.31)0.01.000044467.527-37 ( )0.03.00006
11Soil ProcessingThe first step to processing sticky or clay sediment was to add adequate water to each sediment sample to create a slurry and to put it aside for a few daysWe use the magnet to catch them. The sediment was then poured into a filter, and transferred into another bucket.
12Soil ProcessingThe magnet, was tightly stretched in a Hefty plastic bag, and then immersed in the mixture NOTE: The magnet was moved slowly and gently, to avoid dislodging grains.The magnetic fraction withdrawn from the water. The bag, magnet, and grains were then immersed in a second container of clean water. Withdrawing the magnet from the bag released the grains into the water.
13Soil ProcessingThis process was repeated until only minimal additional grains were extracted. Next, in order to separate excess dirt from the magnetic grains, the bag and magnet were used to retrieve the magnetic fraction from the second container.After removing the magnet, the wet grains stuck to the bag and were transferred onto a small plate.After Drying, the magnetic fraction was weighed, catalogued, and analyzed.
14Extraction of Magnetic Fractions To find micro spherules, the magnetic fraction is extracted. To identify the micro spherules, it is necessary to clean the magnetic fraction with water.To find micro spherules, we dusted the magnetic grains lightly across a white background microscope slide, making it easier to distinguish the spherules.NO MAGNETIC SPHERULES WERE FOUND!
15Extraction of Carbon Spherules, Glass-like Carbon, And Charcoal Carbon spherules have a low specific gravity, so water floatation was used to separate them. Ample water was used for dilution, and the slurry was agitated to free the floating fraction (ARROWS)The floating fraction was captured with a filter.The floating fraction was then placed onto a plate to dry.This was repeated until all floating fractions were removed.To recover the less buoyant fraction of carbon that did not float, the remaining slurry was rinsed and agitated repeatedly. This stratified the sediment and brought the remaining non-floating carbon fraction to the surface of the sediment sample, but beneath the water. Obvious carbon, which included charcoal and glass-like carbon, was separated manually.
16Analysis of Individual Soil Samples The markers revealed from our analysis of sample 1 taken from Miles Point; at a depth of 22.5 inches (57.15 cm) and above the YDB, included: Magnetic Grains (not found)Magnetic Spherules (not found)Carbon Spherules (found)Glass-like Carbon (not found)Charcoal (not found)Nano-Diamonds (found)
17Analysis of Individual Soil Samples The markers revealed from our analysis of sample 2 taken from Miles Point; at a depth of 24.5 inches (62.23 cm) and above the YDB, included: Magnetic Grains (found)Magnetic Spherules (not found)Carbon Spherules (found)Glass-like Carbon (not found)Charcoal (not found)Nano-Diamonds (Un-evaluated)
18Analysis of Individual Soil Samples The markers revealed from our analysis of sample 2 taken from Miles Point; at a depth of 26.5 inches (67.31 cm) and approx. at the YDB, included: Magnetic Grains (found)Magnetic Spherules (not found)Carbon Spherules (found)Glass-like Carbon (not found)Charcoal (found)Nano-Diamonds (Un-evaluated)In addition to the above expected markers, analysis of the magnetic material extracted from this sample revealed an unexpected marker whose full significance is now being investigated at the University of New Hampshire by Botanist Dr. Barry Rock using Scanning Electron Microscopy (SEM).7. Magnetite Impregnated scorched Wood Fragments (possibly pre-fossilized)
19Analysis of Individual Soil Samples The markers revealed from our analysis of sample 2 taken from Miles Point; at a depth of inches ( cm) and approx. at or below the YDB, included: Magnetic Grains (found)Magnetic Spherules (not found)Carbon Spherules (found)Glass-like Carbon (found)Charcoal (found)Nano-Diamonds (Un-evaluated)Magnetite Impregnated scorched Wood Fragments (possibly pre-fossilized) (found)
20Results Impact Markers Magnetite impregnated wood fragmentsScorched magnetite, pre-fossilized wood fragmentsMagnetite impregnated and nearly fossilized wood fragments that appear to show some evidence of scorching to the point of becoming charcoal.Charcoal fragmentsGlass-Like Carbon fragments
21ResultsImpact MarkerCarbon SpherulesCarbon Spherules (probably droplets of melted tree sap) in a variety of colors ranging from pearl to dark gray.Nano-diamonds presumably created in an environment of intense heat and pressure (shown with a millimeter scale)Nano DiamondsCloser Look at Nano Diamonds
22Coring at Kimbel Bay, NC Purpose Give full vertical sedimentary profile of 126 inches underground.We know that markers came out of the Kimbel baySo we collected soil samples to process in future work.We were going to use the GPR at the core site, but 3 flat tires prevented it.
23Ground Penetrating Radar PurposeTo see what was beneath the lake bed.To see if there was any indication that the bay was caused by an impact (e.g. Multiple Rims or Paleo-depressions)Multiple Rims
25Acknowledgements Special Thanks to: Dr. Linda Hayden Dr. Malcolm LeCompteAllen WestDavid KimbelGeorge HowardBob LangenburgSuntzu “Team Mascot”Audience
26ConclusionThe hypothesis that the Younger Dryas (YD) was triggered by an (extraterrestrial) ET impact appears to be confirmed by our results. Our research revealed a number of constituents that support the comet impact hypotheses from soil samples extracted from the bank of the Chesapeake Bay at Miles Point, MD. Most of these constituents, including charcoal, glass-like carbon, carbon spherules (possibly melted tree sap), and scorched wood fragments suggest major forest fires preceded the YD cooling. The carbon spherules were discovered in all the samples, while the rest of the markers were concentrated in samples 3 and 4.Magnetite discovered embedded in the scorched wood fragments may have been a direct result of the impact or normal mineralization due to the process of fossilization. Magnetite spherules were found embedded in downed trees at the site of the Tunguska, Siberia impact in 1908.Samples of the Miles Point scorched wood fragments have been forwarded to Dr. Barry Rock at the University of New Hampshire for further testing to determine whether or not the wood fragments are pre-fossilized.Microscopic examination revealed traces of nano-diamonds in soil samples 3 and 4, which are direct evidence of an ET impact.Taken together these markers suggest that a significant environmental calamity occurred 12,900 years ago with many of the expected characteristic side effects characteristic of an ET Impact.
27Future WorkProcessing and Analyzing of Stratigraphic soil samples collected at Eurefarm, Cross Neck Road, Hertford, North Carolina.Collection and Analysis of additional Stratigraphicsoil samples from at or near Miles Point Maryland.Continued Analysis of Ground Penetrating Radar data from the Kimbel Bay.Processing and Analyzing soil core samples collected at the Kimbel Bay.More GPR surveys of other Carolina Bays.
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